This invention relates to a multi-mode reproducing apparatus preferably of the electrostatographic type. The apparatus includes means for copying documents selectively at a plurality of magnifications.
A variety of electrostatographic reproducing machines are commercially employed which have different modes of operation. One type of machine utilizes a moving original exposure system wherein an original document is moved past a fixed slit optical system for projecting an image onto the moving photoconductive surface. These machines include a means for changing the magnification of the projected image to provide reduction copies. Exemplary of patents in this area is U.S. Pat. No. 3,076,392, to Cerasani et al, and 3,649,114 to Vlach et al.
Other machines have been adapted to copy stationary original documents at a variety of magnifications or reductions through the use of a scanning optical system. Exemplary of patents in this area are U.S. Pat. Nos. 3,476,478, to Rees, Jr.; 3,542,467 to Furgeson; 3,614,222 to Post; and 3,837,743 to Amemiya. Another approach which has been utilized for projecting images for reproduction at varying magnifications from a stationary original comprises full frame exposure. Exemplary of patents in this area are U.S. Pat. Nos. 3,543,289 to Koizumi; 3,687,544 to Muller; 3,703,334 to Knechtel; and German Offenlegungsschrift 2,154,944 to Libby.
U.S. Pat. Nos. 3,703,334 to Knechtel and 3,837,743 to Anemiya set forth above are also significant in that they disclose the use of a separate reflector or add reflectors, respectively, which are selectively positionable in the optical path for changing the conjugate distance of the optical system for providing varying magnifications.
The aforenoted machines are adapted to provide one or more modes of copying having different magnifications. In the optical systems of these machines, some means is usually provided for changing the conjugate relationship of the object and image sides of the projection lens. This may be accomplished by translating the lens between different positions for different projected image magnifications or in accordance with an alternative approach by utilizing more than one lens whereby different lenses are selectively positionable in the optical path, depending upon the projected image magnification desired. See, for example U.S. Pat. No. 3,779,642 to Ogawa.
The systems which are described in the various patents and applications above noted are probably well suited for their intended purposes. Those systems can be readily applied to machines which will be newly built. There already exists, however, a substantial number of reproducing machines in commercial use which are adapted to provide copies of a document at a single projected image magnification. A variety of optical systems have been utilized to provide the optical exposure in these commercial units. Modification of those optical systems to provide multiple modes of projected image magnification would require extensive alteration. In accordance with the present invention it is desired to modify the optical systems to provide variable magnification in a way which can be readily implemented in existing machines with a minimum of alteration.
Other forms of multi-mode copiers are available commercially. For example, in the Xerox 3100 LDC machine an optical system is provided which enables the machine to copy from a stationary original in a first scanning mode or from a moving original in a second fixed optical mode. This latter mode is particularly adapted for copying documents larger than the conventional viewing platen size. U.S. Pat. No. 3,900,258 to Hoppner et al [1] is illustrative of a machine similar in many respects to the 3100 LDC machine.
Reproducing apparatuses including the capability of making copies from both moving and stationary originals are also described in U.S. Pat. No. 3,833,296 to Vola, and in IBM Technical Disclosure Bulletin, Vol. 12, No. 1, at page 173, June 1969.
It has been found desirable, to provide a multimode reproducing apparatus having various unique features of the 3100 LDC machine, including its extremely compact size, but also having the capability of reduction copying.
One approach to such a machine is described in U.S. application Ser. No. 588,971 to Hoppner et al [2]. In that application a multimode reproducing apparatus is provided including both moving and stationary original exposure modes, with at least two modes of moving original exposure at differing copy image magnifications.
In the apparatus of the Hoppner et al [2] application, only two modes of moving original exposure are shown although additional modes could be provided. One at a nominal magnification wherein the add mirror is positioned out of the optical path and one at a reduced magnification wherein the add mirror is positioned in the optical path.